The Space Elevator - Structure Designed to Transport Material

The Space Elevator

Structure Designed to Transport Material

The Space ElevatorStructure Designed to Transport Material

The Space Elevator will reduce the cost of getting
from earth to space. It will also allow us to take very large payloads
into space very easily, very safely. Because of that, we can build
cities on the moon. We can build space stations. We can build large
solar arrays in space to collect energy from the sun and beam it down to
earth. How would the space elevator affect the average person?
Through
for example much faster telecommunication rates -- you can have any
kind of data rates you want, and videophones will be as common as a cell
phone. And the solar power energy we'll collect can relieve our
dependence on oil. That in itself will change a lot of things it will
reduce pollution and it will change world politics, hopefully even
stopping some of the conflicts.

A space elevator is a proposed structure designed to transport material from a celestial body's surface into space.

Many variants have been suggested, all of which involve traveling along a
fixed structure instead of using rocket powered space launch.

The concept most often refers to a structure that reaches from the
surface of the Earth on or near the Equator to geostationary orbit (GSO)
and a counter-mass beyond.

A space elevator is a proposed structure designed to transport material
from a celestial body's surface into space. Many variants have been
suggested, all of which involve traveling along a fixed structure
instead of using rocket powered space launch.

The concept most often refers to a structure that reaches from the
surface of the Earth on or near the Equator to geostationary orbit (GSO)
and a counter-mass beyond.

The concept of a space elevator dates back to 1895 when Konstantin
Tsiolkovsky proposed a free-standing "Tsiolkovsky" tower reaching from
the surface of Earth to geostationary orbit.

Most recent discussions
focus on tensile structures (specifically, tethers) reaching from
geostationary orbit to the ground.

This structure would be held in tension between Earth and the
counterweight in space like a guitar string held taut. Space elevators
have also sometimes been referred to as beanstalks, space bridges, space
lifts, space ladders, skyhooks, orbital towers, or orbital elevators.

Current technology is not capable of
manufacturing practical engineering materials that are sufficiently
strong and light to build an Earth-based space elevator.

Recent
conceptualizations for a space elevator are notable in their plans to
use carbon nanotube or boron nitride nanotube based materials as the
tensile element in the tether design, since the measured strength of
microscopic carbon nanotubes appears great enough to make this
theoretically possible.

Technology as of 1978 could produce
elevators for locations in the solar system with weaker gravitational
fields, such as the Moon or Mars. A further issue is that for human
riders on an Earth-based elevator, space radiation due to the Van Allen
belts would, if unshielded, give a dose well above permitted levels.
This would not be an issue for non-living cargo, however.The Space Elevator - Animation

The Space Elevator, animated in this video as envisioned by Bradley
Edwards, the most current proponent of this means of getting into space
cheaply.

The initial research behind this video was funded by the NASA Institute of Advanced Concepts.

A space elevator could also be constructed on other planets, asteroids and moons.

A Martian tether could be much shorter than one on Earth. Mars' surface gravity is 38% of Earth's, while it rotates around its axis in about the same time as Earth.

Because of this, Martian areostationary orbit is much closer to the surface, and hence the elevator would be much shorter. Current materials are already sufficiently strong to construct such an elevator. However, building a Martian elevator would be complicated by the Martian moon Phobos, which is in a low orbit and intersects the Equator regularly (twice every orbital period of 11 h 6 min).

A lunar space elevator can possibly be built with currently available technology about 50,000 kilometers (31,000 miles) long extending through the Earth-Moon L1 point from an anchor point near the center of the visible part of Earth's moon.

However, the lack of an atmosphere allows for other, perhaps better, alternatives to rockets.

On the far side of the moon, a lunar space elevator would need to be very long (more than twice the length of an Earth elevator) but due to the low gravity of the Moon, can be made of existing engineering materials.

Rapidly spinning asteroids or moons could use cables to eject materials to convenient points, such as Earth orbits; or conversely, to eject materials to send the bulk of the mass of the asteroid or moon to Earth orbit or a Lagrangian point.

Freeman Dyson, a physicist and mathematician, has suggested using such smaller systems as power generators at points distant from the Sun where solar power is uneconomical. For the purpose of mass ejection, it is not necessary to rely on the asteroid or moon to be rapidly spinning.

Instead of attaching the tether to the equator of a rotating body, it can be attached to a rotating hub on the surface. This was suggested in 1980 as a "Rotary Rocket" by Pearson and described very succinctly on the Island One website as a "Tapered Sling".